The number of electronic components mounted on the electronic circuit board is increasing in accordance with the multifunctionalization of electronic devices in recent years. The electronic devices are also being miniaturized, and it is strongly desired to improve the packaging density of electronic components for achievement in both multifunctionalization and miniaturization of the components. For improvement in the packaging density, it is necessary to enhance the performance and miniaturization of various kinds of electronic components, and miniaturization and high performance of thin film capacitors, which are one of the electronic components, are also demanded increasingly strongly.
Conventionally, metal oxide materials have been widely used as dielectric materials for the thin film capacitors, and the improvement in material properties have been advanced for many years so as to obtain thin film electronic components having higher functions. However, the improvement in properties of electronic components based on metal oxides has been reaching its limit, and new materials having higher properties are strongly required.
For further improvement in properties of the thin film capacitors, materials having high dielectric properties other than metal oxides have been recently developed. Examples of the materials having high dielectric properties other than metal oxides include a metal oxynitride material where a part of oxygen atoms of oxygen octahedron having a perovskite crystal structure is substituted with a nitrogen atom. Incidentally, the perovskite structure is a structure typically represented by ABX3 (X; O, N, C, F).
Patent Literature 1 discloses a technique relating to a metal oxynitride having a specific permittivity of 11000, which exceeds the relative permittivity obtained with the conventional barium titanate. However, this relative permittivity is not measured from a bulk sintered body obtained by sintering grains of metal oxynitride as an ordinary dielectric, but is calculated from pellets obtained by performing a CIP pressing to the powder of metal oxynitride. It is difficult to obtain sufficient insulation property with such a powder green compact.
Patent Literature 2 discloses that relative permittivity of a sintered body of a metal oxynitride having a perovskite structure is evaluated and its frequency dependency is small, but does not clearly disclose the value of the relative permittivity. In addition, Patent Literature 2 does not verify whether the sintered body of the produced oxynitride has a sufficient insulation property.
Non-Patent Literature 1 describes an oxide ferroelectric having a perovskite layered structure different from the above-mentioned perovskite structure. In Non-Patent Literature 1, substances having a perovskite layered structure are mainly classified into three groups. The first is a substance called Ruddlesden-Popper type and represented by the general formula of Am+1BmO3m+1. Specific examples of the first includes La2-xSrxCuO4, which is a high temperature superconducting oxide. The second type is a substance called Aurevilleus type and represented by the general formula of Am−1Bi2BmO3m+3. Specific examples of the second type include SrBi2Ta2O9, which is a Bi based ferroelectric material expected to be applied to a ferroelectric thin film memory. The third is a substance called a perovskite slab structure and represented by the general formula of AnBnO3n+2. In case of n=4 in the general formula of AnBnO3n+2, the substance is represented by a composition formula of A2B2O7. Representative examples of such a substance include Sr2Ta2O7 and La2Ti2O7.
On the other hand, there is a substance having a pyrochlore structure as a structure represented by the same composition formula of A2B2O7. Specifically, examples of this substance include Dy2Ti2O7, which is a magnetic body. Incidentally, it is generally known that the pyrochlore structure has the same composition formula as that of the perovskite structure, but its crystal structure and dielectric property are greatly different from those of the perovskite structure.
Non-Patent Literature 2 discloses that a metal oxynitride raw material powder and a carbon powder are fired at a high temperature to obtain a metal oxynitride as a sintered body.